Vehicle windshields typically include a pair of bent glass substrates laminated together via a polymer interlayer such as polyvinyl butyral (PVB). It is known that one of the two glass substrates may have a coating (e.g., low-E coating) thereon for solar control purposes such as reflecting IR and/or UV radiation, so that the vehicle interior can be more comfortable in certain weather conditions.
Conventional windshields are made as follows. First and second flat glass substrates are provided, one of them having a low-E coating sputtered thereon. The pair of glass substrates are washed and booked together (i.e., stacked on one another), and then while booked are heat bent together into the desired windshield shape at a high temperature(s) (e.g., 8 minutes at about 600-625 degrees C.). The two bent glass substrates are then laminated together via the polymer interlayer to form the vehicle windshield.
Unfortunately, yields for such windshields are often as low as 70% (i.e. up to 30% may have to be thrown out). These rather low yields are caused by a number of factors, some of which are now described.
The glass substrates are typically made by the known float process which is very efficient and effective. During the glass making process, SO2 is often used and tends to collect on the non-tin side of the glass. The presence of SO2 deposits at the glass surface is not an immediate problem, but upon heat treatment (HT) at the high glass bending temperatures mentioned above the presence of this material can cause blemishes or imperfections (e.g., sometimes known as fish-eyes) to appear in the final vehicle windshield. Other undesirable surface deposits which can occur on the glass surface and which may ultimately cause significant blemishes or imperfections in a resulting windshield include: suction cup marks made during handling, grease pencil marks, glove marks, spray paint marks, scratch(es), thin film(s) of impurities, stains, oil/grease, and/or the like. Again, one or more of these undesirable deposits can result in windshield blemish(es) which may cause the windshield to have to be thrown away thereby resulting in low yields at a significant cost to the windshield manufacturer.
In view of the above, a need in the art exists for improving yields in vehicle windshield production and/or reducing the occurrence of significant blemishes in vehicle windshields (e.g. fish-eyes). It is an object of certain embodiments of this invention to fulfill one or more of these needs, and/or other needs which may become apparent to the skilled artisan from the description herein.
An object of this invention is to provide a method of making vehicle windshields and/or other laminated windows in an improved manner.
Another object of this invention is to provide a method of making vehicle windshields and/or other laminated windows in a manner so as to improve production yields and/or reduce the occurrence of significant blemish(es) or imperfections therein.
Another object of this invention is to, in a method of making a vehicle windshield or other laminated window, ion beam mill a surface of at least one of the glass substrates prior to lamination in order to remove certain undesirable surface deposits. Advantageously, such ion beam milling has been found to improve yields and/or improve window quality.
Another object of this invention is to fulfill one or more of the above-listed objects and/or needs.
Generally speaking, certain example embodiments of this invention fulfill one or more of the above listed objects and/or needs by providing a method of making a vehicle windshield, the method comprising: providing first and second glass substrates; on beam milling at least one surface of the first glass substrate so as to remove at least 2 xc3x85 of glass from at least a portion of the first substrate and form an ion beam milled surface of the first substrate; sputtering a coating, including at least one infrared (IR) reflecting layer, on the ion beam milled surface of the first substrate; and laminating the first substrate with the coating thereon to the second substrate via a polymer inclusive interlayer so that the coating and the interlayer are provided between the first and second substrates.
Other example embodiments of this invention fulfill one or more of the above listed objects and/or needs by providing a method of making a laminated window, the method comprising: providing first and second glass substrates; ion beam milling at least one surface of the first glass substrate so as to remove at least 2 xc3x85 of glass from at least a portion of the first substrate and form an ion beam milled surface of the first substrate; forming a coating on the ion beam milled surface of the first substrate; and laminating the first substrate with the coating thereon to the second substrate via a polymer inclusive interlayer so that the coating and the interlayer are provided between the first and second substrates.
Still other example embodiments of this invention fulfill one or more of the above-listed objects and/or needs by providing a vehicle windshield comprising: first and second glass substrates laminated to one another via a polymer inclusive interlayer; wherein at least one surface of the first glass substrate is ion beam milled; and wherein the windshield has a visible transmittance of at least 70%.
Yet other example embodiments of this invention fulfill one or more of the above-listed objects and/or needs by providing a method of making a vehicle windshield with reduced haze, the method comprising: ion beam milling a first substrate, laminating the first substrate to a second substrate via an interlayer to form the windshield, and wherein the ion beam milling causes haze in the windshield to be reduced by at least 20%.
Still other example embodiments of this invention fulfill one or more of the above-listed objects by providing a method of making a window unit, the method comprising: providing first and second glass substrates; ion beam milling at least one surface of the first glass substrate so as to remove at least 2 xc3x85 of glass from at least a portion of the first substrate and form an ion beam milled surface of the first substrate; forming a coating on the ion beam milled surface of the first substrate; and coupling the first substrate with the coating thereon to the second substrate so that the coating is provided between the first and second substrates. In this regard, the window unit may be a vehicle windshield, an insulating glass (IG) window unit, or any other type of window unit.